Investment mold box



July 7, 1925. 1,545,061

s. E. NOYES INVESTMENT MOLD BOX Filed Aug. 14, 1924 ghwnhw Stanleyl'.Myrs Patented July 7, 1925.

UNITED STATES STANLEY E. NOYES, OF LOS ANGELES, CALIFORNIA.

INVESTMENT MOLD BOX.

Application filed August 14, 1924. Serial R0. 731,912.

To 117/ rel-om if may concern:

Be it known that I. STANLEY E. Novas, a citizen of the l nited States.residing at Los .ingeles. in the county of Los Angeles and State ofCalifornia, have invented new and useful Improvements in Investment MoldBoxes, of which the following is a specification.

The invention herein set forth relates to a device for forming theinvestment or mold employed in making small castings, and particularlypertains to a mold box which is especially applicable for use in formingthe plastic investment used in molding dental inlays and like smallarticles from the rare metals. such as platinum, gold, silver, and theirvarious alloys.

It is customary in the making of minute castings to form a wax patternof the objeet to be cast, then forming a mold or investment byencompassing the wax pattern in a body of plaster, usually made fromplaster of Paris; a mixture of the plaster of Paris and water beingpoured around the pattern in a box containing the wax pattern. and itsaccompanying stems for forming the necessary feed passages in the mold.The plaster is allowed t set and is dried, uhereu 'ion the mold body isheated to melt the wax. which is then poured from the mold body. therebyforming an investment having the desired mold avities.

An object of the invention is to provide a mold box for forming suchinvestments, which is so constructed as to quicken the setting anddrying of the plastic by absorhing moisture therefrwnn, and in so doingserve to render the body of the investment more dense and compact andthereby eliminating detrimental shrinkage and distortion of theinvestment on subjecting it to heat.

Another object is to provide an investment mold box which embodies anabsorptive shell or jacket against which the plastic for forming theinvestment contacts, and which serves to form the sidewall boundary ofthe investment body.

A further object is to provide an absorptive shell or jacket which is soformed and constructed that it may be readily applied to and removedfrom a metallic investment reinforcing frame.

With the foregoing objects in view, to gether with such other objectsand advantages as may subsequently appear, I carry the invent on intoeffect. by employing the parts and the construction. arrangement andcombination of pa ts. or the equivalents tl: reof. substantially asillustrated in the accompanying drawing, in which:

Figure l a perspective icw of the mold box:

l ig. is a view of same as seen in vcrtical section:

Fig. 3 is a view in perspective of the reinforcing and retaining frame;

Fig. l; is a perspective view of the absorption shell; and

Fig. 5 is a detail in cross-section as seen on the line -D of Fig.

Referring to the drawings more specifiiilly indicates a metallic frameadapted to serve as a retainer and reinforcement fol the investmentbody, and B designates the absorptive shell or jacket which is adaptedto encompass the frame A.

The frame is here shown as comprising a series of annuli or rings C, D,and E, mhich ar of corresponding size and are arranged in spacedsuperposed relation; be ing connected together by vertical posts l (l.ll. and l, which are arranged ((]lll distant apart and extend from theupper and lower sides of the intermediate annules l) to the adjacentfaces of the end annules and l The members of the frame are preferablycast of metal and form in their ensemble :1 one piece unitary framestruc" ture which is here shown as being of gen eral cylindrical form.

The shell 1- is in the form of an open ended cylinder and is adapted toreceive the frame A which is inserted within the shell as shown in lignres l and E2.

The shell is formed of any suitable HIOlS ture absorptive material; anunsized paper being found to answer the purpose very satisfactorily andwhich paper may be wound spirally in superposed layers to form a tube ofsuitable length that may be cut to the desired lengths in the samefashion as is employed in the manufacture of the ordinary paper mailingtubes of ('(HlllllPlU. It is desirable, however, that the shell be ofsuch absorptive character as to readily absorb moisture somewhat in themanner of blotting paper, and hence a loose fiber paper is preferablyemployed in its construction.

The shell B is formed of a length approximating that of the frame A,being preferably formed of a ltngth slightly (ill greater than that ofthe frame. so as to project a short distance beyond the ends thereof. asshown in Fig: 2.

' In the operation of the invention, the retaining member A is insertedin the shell as shown in Fig. 2, and the wax pattern mounted in the box.thus formed. in the usual mannr. whereupon the box is placed with one ofits; open ends seating on a slab in the usual fashion. and the plasterof Paris mixture is then poured into the open upper end of the mold box.The absorptive wall or shell immediately absorbs water from the mixture,and in so doing acts to quicken the wet of the plaster and also servesto render the plaster ma;-;s more dense and compact, and whereby theresultant invastment will have little or no porosity. The rapidity ofthe set of the plaster is such that it may be dried in a few momentsafter being poured and the plaster finally dried and heated to removethe wax pattern without distortion of the investment.

While I have shown and described a speeific embodiment of the invention.I do not limit myself to the exact construction herein set forth, andmay employ such modi lications and changes as come within the scope ofthe appended claims.

I claim:

1. An investment mold box having a. wall formed of absorptive materialand adapted to absorb moisture from the plaster poured into the mold.

2. An investment mold box comprising a retaining: frame and anabsorptive shell surrounding the frame.

3. An investment mold box comprising a frame formed of a series ofspaced rings connected to;::ther in axial alignment, and an open endedtubular shell formed of absorptive material, surrounding said frame.

l. In an investment mold box, a cylin drieal open ended tube formed ofabsorptive material.

STANLEY E. NOYES.

